Revert "Gruntfile.js: Change the watch sequence"

This reverts commit 51d3ed51775298acba32059db066009081efc35f.
The sequence is right, revert it.
Gruntfile.js: rebuild the site after all tasks are done

Doing jeklly build after all tasks are done

Signed-off-by: AceLan Kao <acelan@acelan.idv.tw>